Compare two object arrays?

Question

I need to compare 2 arrays in Javascript, one that returns from a Mongodb query and the other comes from the email provider.

The two comparison criteria are the email ID and the box to which it belongs, and the email will be discarded if THE TWO criteria match, otherwise the email will be saved in the bank.

So far everything ok, the problem is that I do not know the logic nor the methods to do it correctly, I have tried using 2 for and none of it worked.

Server:

let dados = [];
    for (let l = 0; l < array.length; l++) { //array é o vetor com os emails que vem do provedor
        dados.push({
            idEmail: array[l].id,
            remetente: array[l].remetente,
            destinatario: array[l].destinatario,
            assunto: array[l].assunto,
            texto: array[l].texto,
            box: flag
        });
    }
    let pesquisa = {'idEmail': {$ne: dados.idEmail}, 'box': {$ne: dados.box}};
    db.open(function (err, mongoclient) {
        mongoclient.collection('emails', function (err, collection) {
            collection.find(pesquisa).toArray(function (err, results) {
                if (err){
                    console.log(err);
                    mongoclient.close()
                } else {
                let comp = [];
                for (let a = 0; a < results.length; a++) {
                    comp.push({
                        id: results[a].idEmail,
                        caixa: results[a].box
                    });
                }
                for (let l = 0; l < comp.length; l++) {
                    if (comp[l].idEmail === dados[l].idEmail && comp[l].caixa === dados.box) {
                        console.log('Repetido')
                    } else if (comp[l].idEmail !== dados[l].idEmail && comp[l].caixa !== dados.box) {
                        mongoclient.collection('emails', function (err, collection) {
                            collection.insert(dados, function (err, records) {
                                if (err) {
                                    console.log(err)
                                } else {
                                    console.log(records)
                                }
                                mongoclient.close()
                            })
                        })
                    }
                }
            }
        })
   })

Answer 1

In

comp.push({
   id: results[a].idEmail,
   caixa: results[a].box
});

Your key is referred to as id and in condition is treated as value

sure would be

    if (comp[l].id === dados[l].idEmail && comp[l].caixa === dados.box) {
                            console.log('Repetido')
                        } else {
                        mongoclient.collection('emails', function (err, collection) {
                        collection.insert(dados, function (err, records) {
                            if (err) {
                                console.log(err)
                            } else {
                                console.log(records)
                            }
                            mongoclient.close()
                        })
                    })
    }

also note that your else if contrary to his if making it simply false, just replace it with else.